Why physicians studied astronomy: Zodiac Man diagrams like this one reveal the hidden correspondences between the organs of the body (the microcosm) and the influences of the stars and planets that affect them (the microcosm). The ability to perform technical astrological calculations was one characteristic which distinguished university-educated physicians from other health care practitioners, and so in many universities astronomy was taught within the medical school. Perhaps it is not surprising that Galileo entered the University of Pisa to study medicine.